Electric heater



H. H. c. DUNWOODY.

ELECTRIC HEATER.

APPLICATION FILED FEB. I?, 1.9.22.

Pawne Nov. 28, 1922.

Patented Nov. 28, 1922.

HENRY H. C. DUNWOODY, OF WASHINGTON, DISTRICT OF COLUMBIA.

ELECTRIC HEATER.

Application filed February 17. 1922. Serial No. 537,218.

To all whom it may concern: I

f Be it known that I, HENRY Il. C. DUN- wooDY, brigadier neral, U. S. A., retired, a citizen of the nited States, residing at Washington, in the District of Columbia, have invented certain new and useful Improvements in Electric Heaters; and I do hereby declare the following to be a full,

clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invent-ion relates to electric heaters especially adapted. for heating water and for other purposes, and has for its obJect to provide an apparatus of this character which will be simple in construction, comparatively inexpensive to manufacture, and more efficient in action than those heretofore proosed.

With these and other objects in view, the invention consists in the novel details of construction and combinations of parts more `fully hereinafter disclosed and particularly pointed out in the claims. i

Referring to the accompanying dra-wings forming a part of this specification, in which like numerals designate like parts in all the views:

Figure 1 is a sectional view of an electric heater made in accordance with this invention' re 2 is a viewi similar to Figure 1 showlng a somewhat modified form;

Figure 3 is a bottom 'plan view of the parts shown in Figure 1, looking upwardly;

Figure 4 is a plan View of one form of heating disk; and

Figure 5 is a plan view of a somewhat modified form of heating disk.

1 indicates any suitable handle or support for the heating elements, provided with an enlarged flat like portion 2 to form a casing, and this casin is preferably made of an inner steel or ot er metal core 3 covered with an yinsulating coating 4' preferably of a silicious or porcelain like material. In fact, the entire casing may conveniently be made of what is known on the market as granite ware. The upper end of the handle 1 is provided with an opening 5, through which passes the lead wires 6 and 7 covered by any suitable insulator 8. The flat like portion 2 of the casing is provided with the bulged portion 9 forming an interior annular bead 10 into which may snap the curved lugs 11 rigid with the heating disk 12, all as will be clear from Figure 1. Above said heating disk 12 are. located a plurality of heating disks such as 13 and 14, and the disk 13 is supported from the lowermost disk 12 as by the lugs 15 while the uppermost disk 14 is likewise supported from a lower disk as by the similar'lugs 16. The lead wire 7 is secured to the uppermost disk 14 by any suit.- able means as by the screw connection 18, and the lead wire 6 is secured to the `lower disk l2 as by the screw connection 19. In this particular form of the invention shown in Figure 1, current may enter as by the wire 7, traverse the disk 14, the lug 16, the disk 13, the lugs 15, the disk 12, and then pass out through the wire 6. The disks 12, 13 and 14 are preferably' made of very thin sheet iron or sheet. steel, so that their resistance is relatively high. In addition to this, said disks are further preferably provided with numerous perforations or holes 20, which still further increase the resistance of said disks. y I

It results from this that whether an alternating or a direct current is passed through the said disks in the manner disclosed, they will rapidly heat according to the resistance they offer to such current, and should the lower portion 2 of the casino be immersed in water, to heat the same, the disks being flat and spaced relatively close together, the said disks will be covered with water even though the latter be quite shallow.

It results from this that should one turnwith water and thus ruu no risk of unduly 1 heating the disks when they are not covered with water and thus avoid the .oxidation ofthe same as well as other troubles which are liable to ensue should said disks not be completely immersed. f

When the disks wear out, it is only necessary to snap out the three disks 12, 13 and 14 illustrated in Figure 1, disconnect the lead wires 6 and 7 therefrom, connect up said wires with a new set of disks provided with the spring catches 11, and snap the new set of disks into place, whereupon the heater is ready for use again.

In the somewhat modified form of the invention illustrated in Figure 2, the construction is the same except instead of having a plurality of disks only one disk 25 is employed. 'lhis said disk enables one to use the heater in Water which is still more shallow than is required ttor the torni shown in VFigure l. ln tact as thisdiskQ is located Within, say, 'L; inch or less of the eXtreine insulated lower edge 28 of the casing, the water need not be deeper' than say l inch or a halt a inch betore the disk is completely covered. Said disk is preferably made in the torni illustrated inl Figure, wherein a pluraiityoil holes 2O` are provided as Well a plurality ot slits ,2a-are provided in orde f' to increase the resistance ot the said disk 22.

rlhe i'orin of the disk Qfshoivn in Figure Ll is or rnay be substantially solid throughout. That is to say, the holes-26 shown therein are :l'or the reception et' the connecting screws 18 and 19, see Figures l .and 3, and the current passes throughout the inetal portion et the disk Without being interrupted `by periora-tions.

lt `will thus `be seen that in all the orins l ain enabled to avoidV the over eating .ot the resistor due to the Water not .being sutilciently deepto cover theentire dimensions ot said resistor. liound from actual experience inthe use of a Well known water heateron the marl-:et which provided with a helirall)j arranged .resistoi', unless the Water is ot a sutiioient depth tocover Ythe entire helix olf said re-A sistor, the latter heats unequally, it isv liable to burn out and also to `blovvv `the :inse ot' the ieed line.y `.l1/Vith this 'torni of heater, on the other hand, the resistor elements are fiat, they are in a veryishallow plane, and it results that the Water may. only be, say, inch deep or less `in order toentirely cover said resistors and therefore Vthe `.troubles heretoforey experienceddue to unequal heatings ot theresistors is entirely avoided.

ln addition to' the` above, it is obvious that this particular' 'for-rn oii'heater is useful That is to say, l have `sist v receiving portion provided With an open end and an annular interior depression; a flat resistor elernent provided AWitha spring ,like holding elenient adapted to snap I.into land out of said depression; and electric current conveying wires carried by said handle portion and joiner to said resistor clenient, substantially as described.

2. In an electric heater the combination of a holloivha die portion; a fiat resistor receiving portion provided With an annular vinterior depression; ;a fiatperforatedi disk like resistor element proviced with a spring Alike holding` elernent adaptedito snap `into said depression; and insulated electric'current conveying` Wires carried byl said handle portion andgoined to said resistor` element,

substantially as described. t

3. ln an electric heater the combination ol a casing iliade oi sheet material` having au insulating. covering` and' comprising an elongated handle `portieri, and a Hatreor receiving` portion, provided vwith an open end and an interior annulargroove; a resistor element provided with holding lugs having curved ends adapted tosnap into said groove; and lead Wires passing through said handle portion and joinedto said resistor ele1nent,. substantially as described..

4l. ln an electric heater the combination oi? a casing` rnade oi" sheet material having an insulating covering,` and comprising an elongated handle portion, and aat resister receiving portion provided with an interior annular groove; a. resistor element comprising a plurality ot perforated disks provided With holding' lugs ljiafvingv curved ends adapted to snap finto `said groove; and lead .wires passingthroughsaid handle portions and joined in series to the disks otl said resistor element, substantially as described.

ln testiinonyWhereoi1 l. aiiin my signature.

HENRY ri.y o. nnnivoonr.

Shi

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